Stick to conservative terrain today.
Snowfall will continue to build reactive slabs, and we are uncertain how buried weak layers will react to this new load.
Reports show a layer of surface hoar buried 60 to 100 cm deep is becoming harder to trigger. However new snow may increase the likelihood of triggering this layer, or produce step down avalanches.
Storm snow may trigger easily as it accumulates over weak surfaces. Likely trigger points include deeper deposits of new snow in wind-loaded terrain features.
As storm snow began to accumulate on Thursday, human triggered avalanches were observed to size 1.5.
Operators have been testing the buried weak layers, on Thursday explosive control produced up to size 2 slabs on east facing slopes. The last reported persistent slab avalanche on the buried surface hoar was last Saturday. Triggering becomes more likely as storm snow adds load to the snowpack, most likely in upper treeline and alpine terrain.
By Saturday afternoon, storm totals may reach 50 cm in the Selkirks and around 30 cm elsewhere. This snow accumulates over crusts, surface hoar, and facets. Reports suggest it may be bonding poorly.
A crust formed by the early December rain event is found roughly 60 cm deep, and a layer of surface hoar is found 60 to 100 cm deep. Where it exists, the crust makes it harder to trigger the surface hoar layer, but triggering remains a concern at higher elevations where the crust is less prominent.
The lower snowpack is variable throughout the region, facets found at the ground in shallow snowpack areas.
Friday Night
Cloudy with 5-10 cm of snow in most areas, and up to 20 cm possible in the Selkirks. Southwest winds 40 km/h. Freezing levels below 1000 m.
Saturday
Cloudy with 5-15 cm of new snow. Southwest winds ease, 20-30 km/h. Freezing levels remain below 1000 m with treeline temperatures around -6 °C.
Sunday
Mostly cloudy with a trace of new snow, winds from the northwest 20 km/h. Freezing levels drop to valley bottom, treeline temperature -8 °C.
Monday
Cloudy with a trace of new snow, westerly winds 20-30 km/h. Freezing levels at valley bottom, treeline temperatures -10 °C.
More details can be found in the Mountain Weather Forecast.
